Email is the one notification we all get, which mean that it's easy for your message to get lost in someone else's torrential flood. To improve your chances of getting your message read, keep the subject line between six to ten words.

An analysis of email responses by marketing company Retention Science found that emails with subject lines containing six to ten words were the most effective at getting the recipient to open them up. It's not just brevity that's the soul of wit, it seems. It's also balance. Anything longer or shorter than that and the open rate drops:

Subject lines with six to 10 words perform best, generating a 21 percent open rate, well above industry standard. Those with subject lines containing five or fewer words ranked second with a 16 percent open rate, and those with 11–15 words returned a minimal 14 percent open rate. Despite this, the majority of emails sent (52 percent) had subject lines in the 11-15 word range.

While keeping your subjects short should go without saying in a world where your email is probably going to be read on a mobile phone, don't make it too small. The sweet spot seems to be just enough words to convey an idea without going overboard.